Process of and apparatus for purifying gas



INVENTlI/i I %-//%M 2 Sheets-Sheet 1. 'P. BREDEL.

PROCESS OF AND APPARATUS FOR PURIPYING GAS.

Patented Jan. 26, 1892.

(No Model.

ATTORNEY.

*(NQ Model.) H 2 Sheet-Sheet 2 n 1-". BREDEL. PROGESSQPAND APPARATUS FORPURIFYING GAS. No. 467,605. Patented Jan. 26, 11892.

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WITNESSES: INVENTOI? v UNITED STATES PATENT OFFICE.

FREDERICK BREDEL, OF MILXVAUKEE, VISCONSIN.

PROCESS OF AND APPARATUS FOR PURIFY ING GAS.

SPECIFICATION forming part of Letters Patent No. 467,605, dated January26, 1892.

Application filed July 25, 1891. Serial No. 400,725. (No model.)

To all whom it may concern.-

Be it known that I, FREDERICK BREDEL, a citizen of the United States,residing at Milwaukee,in the county of Milwaukee and State of Wisconsin,have invented certain new and useful Improvements in Cooling andPurifying Illuminating-Gas and I do declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, and to theletters of reference marked thereon, which form a part of thisspecification.

This invention relates to an improved method of eliminating theimpurities of the gas in such a way and at such a time of the processthat the heavier illuminants cannot be absorbed by far. These impuritiesare tar, carbonic acid, sulphureted hydrogen, bisulphide of carbon,ammonia, and other sulphur compounds; The illuminants are propene orpropylene, butene or butylene, &c., and benzol and naphthaline vapors,which latter give the gas a great illuminating power, but which arereadily absorbed by tar as soon as the temperature of the tar fallsbelow 95 Fahrenheit. This new process and statementmoves the tar in sucha way that the gases cannot come in contact with the tar-wetted surfaceswhen the cooling and purifying process proper begins.

Having now given a general outline of the process, I will now commenceto describe same.

On the annexed sheets of drawings the apparatuses are shown in differentsections. Figure 1 is a side view, and Fig. 2 a plan, of the apparatus.

Same figures always have reference to the same apparatus or part ofapparatus.

A is a washer, which will hereinafter be called the cooling-Washer B,the compensator; C, the ammonia-extractor; D, the cooler; E, the pump,and F the storage tank. The cooling-washer A and ammonia-extractor C areapparatuses of the style known as immersion-washers, and similar to theone on which Letters Patent were granted, under No. 380,040, to Mr. Aug.Kloenne, of Dortmund, Germany, under date of March 27,1888. The

is a surface condenseran apparatus similar to one for cooling andcondensing anhydrous ammonia-vapors used in ice and cold-storagefactories. Pump E is a pump specially constructed for pumping ammoniacalliquor or gas-water. Storage-tank F is an ordinary stor age-tank, intowhich the cool ammoniacal liquor is pumped. All the pipes and valvesshown on the different plans are so arranged that the gas and ammoniacalliquor can be conveyed from one apparatus to the other with thenecessary amount of by-pass valves to enable the by-passing and cleaningof one apparatus while the others are in use, and which will readily beunderstood by anybody familiar with the manufacture of gas.

I will now commence to describe the process. The gas, after it has beenmanufactured in the retorts or producer and having passed theexhausters, passes a friction or air or water surface condenser, or bothor all three apparatuses, which are not shown in this plan; but it isnot absolutely necessary to use one of these latter three apparatuses aslong as the gas reaches the inlet G at a temperature of from to 100Fahrenheit, preferably at from to 100 Fahrenheit, and as long as themechanical impurities-such as coke-dust, heavy pitch, ate-have beenremoved, which can be done by either one of the aforesaid condensers orby the necessary length of gas-mains, as the gas will deposit all theseimpurities in a very short time by passing through conduits. From G thegas enters into the cooling-washer A in its bottom section A, where itimmediately has to plunge through ammoniacal liquor, whereby part of thetar drops into the liquor without having a chance to absorb any of theheavy hydrocarbons mentioned'in my general explanation. The temperatureof the gas is thereby lowered also. The gas then passes consecutivelyinto the sections A A A A, where it loses all its tar, and, as saidbefore, all the carbonic acid and as much sulphur as the ammoniacalliquor, which enters atH and which contains a great amount of causticammo'nia, is able to absorb and transform into carbonates andbicarbonatcs of ammonium and sulphates and bisulphites of ammonium. Thegas in the meantime has given .up part of its heat to the ammoniacalliquor and leaves the cooling-washer at I at a temperature of from to 70, and is absolutely free of tar, which it generally is already afterpassing section A or A The sectionsin the cooling-Washer are not limitedto five, but can be more or less. The gas passes from I through thepipes, following direction of arrows K K K K and enters the compensatorB. The gas there is kept at an even temperature of 60 Fahrenheit, andthis compensator has only the duty to fulfill of keeping the gas as nearas possible to a steady temperature of 60, which otherwise would not bepossible, as the flow of ammoniacal liquor which enters at H is nearlyconstant, while the quantityof gas manufactured at differentperiodsduring a twenty-four-hours run is always variable. For economys sakethis compensator might be omitted, but it is advisable not to. The gasleaves the compensator at L, follows the direction of arrows M M M M Mandenters the ammonia-extractor-at N and passes the different sections0' 0 0 C C of said ammonia-extractor O, consecutively, and leaves theextractor at 0 free of ammonia. This apparatusis also not limited tofive compartments, but might-consist of more or less.

To extract the ammonia, clear water, as free as possible of lime, isadmitted at P. This water flows from section to section in the waydescribed in the aforesaid patent, No. 380,040, till it'lea'ves theammonia-extractor G at' R. It is then thoroughly charged with theammonia originally contained in the gas, and partly with sulphates ofammonium. From B it flows in thedirection of arrow Q and entersthe'coolin'g-washer A at I-Ltogether'with other ammoniacal liquor,coming from storage-tank F through pipes S. It goes then from section tosection, as described in Patent No. 380,040, till it leaves the firstsection A of cooling-washer A at T. The water has naturally taken uppartof the heat originally contained in the gas. At T it goes into a tarand light-oil separator U, where the tar and light oil are separatedfromthe liquor and flow through Z and Z to the tar-well, while theammoniacal liquor'leaves the separatorU and goes through V and pipe Vand enters the cooler D at V and passing through the pipes Viwhich arecontinually cooled by cold water, it is cooled down to between 60 andFahrenheit. After the ammoniacal liquor leaves the cooler at V it goesinto distributing tank W, where a quantity of ammoniacal liquor equal toa quantity of clear water admitted at P is discharged at W into theammonia-well, and the balance passes through pipe W- -into pump E,and-is then forced through pipe XV into storage-tank F and repeats theprocess. The position of pump E may be at option either ahead of orafter cooler D. Also tank W may be ahead of cooler D, at option.

Instead of using only one cooling-washer A, it might under certainconditions be advisable to use two, either together or consecutively. Itis not necessary to use a coolingwasher A or ammonia-extractor O of theconstruction shown and described in Letters Patent No. 380,040, for anygood plunger or immersion washer might be substituted for either ofthem, and if a rotating Washer should be available such a one may besubstituted for ammonia-extractor C. For compensator B any multitubularcondenser having sufficient water capacity might be substituted. Forcooler A any water cooler might be substituted. If it is deemedadvisable to remove all the sulphur-impuritiesout 0f the gas with thispurifying-machine, it is necessary that there should be enough-am moniain the gas to chemically bind all the carbonic-acid and sulphurcompounds contained in the gas. This condition is scarcely everfulfilled. To increase the capacityofth s purifying-machineitisnecessary to makemore austic ammonia available to do this work. Thisis done by letting all-the ammoniacal liquor which comes from thehydraulic main and condensation ahead of this machine, which liquorcontains a large amount of caustic ainmonia, enter either by gravityorbypumprng it into any of the compartments of th'ewashers A or 0,preferably in compartments C C or A It naturally must not-'be-introduced1n O or 0 This introduction can bedone in anyway which might suggestitself, or as shown on plan 1 at'P and H; butthis amount of causticammonia will generally not be sufficient to freethe gas of allits-impurities; as it forms-carbon and sulphur-compounds-of ammonia. If,therefore, the complete purification of the gas by this apparatusisdeemed necessary and advisable, instead of, as :it is now generallydone, passing the gas through iron-oxide orlime purifiers after leavingthis apparatus, an additional quantity of caustic ammonia in the shapeofeither aqua-ammonia in its crude or purified stateor in the shape ofanhydrous ammonia, the latter-preferable in gas form, has to beprocured.

As there are different processes'well known to everybody conversed inthe art, I will not try to explain the processes of manufacturing eitheraqua or anhydrous ammonia here, but only the way they have to be used.If aqua-ammonia is used, it is preferable to use a weak solution notcontaining more than from ten to eighteen per cent. of ammonia,

(NH,,,) as otherwise the loss by evaporation would be too great. Thissolution could best be introduced in the necessary quantities-at either0, A or A If'anhydrous or an ammonia gas is used, then it should best-bemixed with the gas before it enters the coolingwasher A. The quantity ofammonia re quired for the complete purification of the gas would differaccording to the impurities originally contained in the gasmanufactured, as all the time sufficient ammonia has to be present toabsorb by neutralization or chemical combination the impurities of thecrude gas.

I am perfectly aware that plunger-washers have been used before, but donot know, to my best knowledge and belief, that they have ever been usedfor cooling the gas, by which is meant to bring the gas from a hightemperature to such a temperature where the rational elimination ofammonia is possible. This work has up to now been done by what is knownas air or water condensers, which offered the passing gas largetar-wetted surfaces, which tar being at a lower temperature than thepassing gas readily absorbs the heaviest of the olefiant gases and thebenzol and naphthaline vapors, which latter are the best illuminants.Furthermore, by so chilling the gas in the presence of tar thecondensation into and formation of naphthaline crystals, commonly knownas naphthaline, is made possible, while, as is done in my apparatus andprocess, the formation of such naphthaline crystals by cooling the gasthrough the medium of direct contact with more or less causticammoniacal liqnorbecomes impossible, and the naphthaline or benzolvapors remain as a more or less permanent vapor in the gas.

In the following claims the cooling of the gas is always understood tobe the process of bringing the gas safely over its critical coolingmoments, which lie for the formation of naphthaline crystals below 95Fahrenheit in the presence of tar, and which formation is impossiblewhen all the tar is removed by immersion of the gas in more or lesscaustic ammoniacal liquor before it reaches the temperature of 74Fahrenheit.

Having thus described the process and dif-. ferent apparatuses used, Iclaim as new and as my invention- 1. The process of cooling andcompletely or partly purifying coal or carbureted watergas, whichconsists in passing the gas through an immersion or plunger washer whileit is yet at a temperature which would prevent the partial condensationof benzol and naphthaline vapors or the absorption of same by tar,cooling the gas gradually by immersion in and passing through ammoniacalliquor, and then passing it through an ammonia-extractor of any form,substantially as and for the purpose specified.

2. The combination of a cooling-washer A, a compensator B, anammonia-extractor C, cooler D, pump E, with storage-tank F,substantially as and for the purpose specified.

In testimony whereof I affix my signature in presence of two witnesses.

FREDERICK BREDEL.

\Vitnesses:

THEo. KRAUSE, FRANK M. HOYT.

